Create pii_masking.py

pii_masking.py

@@ -0,0 +1,46 @@
+import re
+from typing import Dict
+
+# PII regex patterns
+PII_PATTERNS: Dict[str, str] = {
+    "EMAIL": r"[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+",
+    "PHONE": r"\b\d{10}\b",
+    "CREDIT_CARD": r"\b\d{4}[- ]?\d{4}[- ]?\d{4}[- ]?\d{4}\b",
+    "AADHAAR": r"\b\d{4}\s?\d{4}\s?\d{4}\b",
+}
+
+
+def contains_pii_regex(text: str) -> bool:
+    """Return True if any configured PII regex pattern matches the text."""
+    for pattern in PII_PATTERNS.values():
+        if re.search(pattern, text):
+            return True
+    return False
+
+
+# Masking function
+def mask_pii(
+    text: str,
+    user_tier: str = "free"
+) -> str:
+    """
+    Masks PII in the given text based on user tier.
+
+    free        -> full masking
+    enterprise  -> partial masking (future)
+    internal    -> no masking (future)
+    """
+
+    if user_tier == "internal":
+        return text  # no masking
+
+    masked_text = text
+
+    for pii_type, pattern in PII_PATTERNS.items():
+        masked_text = re.sub(
+            pattern,
+            f"[MASKED_{pii_type}]",
+            masked_text
+        )
+
+    return masked_text